DE102019111185A1 - Clamping device for a screw connection - Google Patents

Abstract

Clamping device for a screw connection consisting of a threaded bolt and a threaded nut, with a support tube (8) surrounding the threaded nut, a cylinder housing (7) as an extension of the support tube (8), a piston that can be moved in the cylinder housing (7) by means of hydraulic pressure, one through the Piston axially removable interchangeable bushing (12) which is provided with an internal thread (13) for screwing the interchangeable bushing (12) to the threaded bolt, and a driver (16) arranged within the support tube (8) and connectable to the threaded nut in a non-positive or positive manner . A gear arrangement (15) is located between a drive element (35) rotatably mounted outside the support tube (8) and provided with a tool surface (38) for attaching a hand tool (10) and the driver (16). In order to safely avoid excessive forces when tightening or turning the threaded nut with simple, mechanical means, part of the gear arrangement (15) is a torque-dependent clutch (30).

Description

The invention relates to a clamping device for a screw connection consisting of a threaded bolt and a threaded nut, with a support tube surrounding the threaded nut, a cylinder housing as an extension of the support tube, a piston that can be moved in the cylinder housing by means of hydraulic pressure, an interchangeable bushing which can be axially driven by the piston and which is equipped with a Internal thread is provided for screwing the interchangeable bushing with the threaded bolt, a driver arranged inside the support tube and connectable to the threaded nut in a non-positive or positive manner, and a gear arrangement between a drive element rotatably mounted outside the support tube, which is provided with a tool surface for attaching a hand tool, and the driver.

Tensioning devices for tensioning screw connections with these features are from the DE 10 2004 043 145 B3 or the WO 2008/092768 A2 known. The clamping device has a hydraulic clamping cylinder which is provided with a gear on the outside. While hydraulic pressure is being fed into the clamping cylinder, the threaded nut is screwed in. For this purpose, a support tube, which forms the lower part of the clamping cylinder, has a driver in the form of a rotary sleeve surrounding the threaded nut in a form-fitting manner. The rotary sleeve is driven by hand by means of a torque wrench attached to a tool surface, a gear arrangement forming the drive path between the tool surface for the torque wrench and the rotary sleeve. A drive housing is attached to the outside of the clamping device to accommodate and pivot the individual gear elements of the gear arrangement. The use of the torque wrench as a hand tool for turning the nut allows a pre-setting of the release value, which, if handled correctly, avoids over-tightening or turning the threaded nut. A prerequisite, however, is that the prescribed torque value for the screw connection is correctly set by preselecting the release value. This is not always guaranteed in practice, since the same torque wrench is also used for other purposes, for example for screwing the interchangeable socket arranged in the clamping cylinder onto the free end of the threaded bolt. An additional check is therefore required to determine whether the release value currently set on the torque wrench is matched to one or the other application. In addition, although a manual torque wrench can signal that a certain torque has been reached, it cannot avoid a torque exceeding this.

The relevance of the problems mentioned also clearly shows the screw tensioning device according to FIG WO 2010/054959 A1 . In this case, it is proposed to attach an express reference to the maximum torque on the outside of the drive housing, which receives the gear unit for tightening the threaded nut.

With one of the U.S. 5,452,629 known screw tensioning device, the tightening or unscrewing of the threaded nut is not done by hand, but using a drive that is only intended for this purpose. An electric motor serves as the drive, the output of which is controlled by monitoring the electrical resistance. The electrical resistance, which increases with the drive load, is used to interrupt the further voltage supply of the electric motor and thus to avoid excessive tightening torques on the threaded nut. The ones in the U.S. 5,452,629 The proposed solution is complex in terms of equipment, since it requires its own electric drive only for tightening or unscrewing the threaded nut, as well as control devices in the electrical supply of the drive.

The invention is based on the object of reliably avoiding excessive forces when tightening or unscrewing the threaded nut in a screw tensioning device operating with a hydraulic tensioning cylinder with simple, mechanical means.

To solve this problem, a clamping device for a screw connection with the features of claim 1 is proposed.

In this clamping device, part of the gear arrangement by means of which the screw nut is screwed in is a torque-dependent clutch. This clutch can, for example, be a friction slip clutch which slips above a certain torque threshold. The torque with which the threaded nut is retightened or screwed in during the activation of the hydraulic clamping cylinder is thus subject to a clear restriction that cannot be exceeded even in the event of incorrect operation. This restriction is largely independent of the actions of the user. The operator is not required to make the correct settings first, in particular to set the correct trigger value when using a hand torque wrench. In addition, the torque-dependent clutch reliably ensures that maximum values cannot be exceeded.

The use of a special torque wrench is not necessary; rather, simpler hand tools can also be used reliably, provided they are suitable for attachment to the existing tool surface.

Preferred configurations of the clamping device are given in the subclaims.

According to one embodiment, the torque-dependent clutch is designed as an overload clutch and preferably as a slip clutch. This enables the flow of power until a certain torque value is reached, whereas it interrupts the flow of power once this torque value is exceeded.

According to one embodiment of the tensioning device, components of the torque-dependent clutch are clutch partners supported against one another in a pressure-loaded manner. The first coupling partner is in an indirect or direct rotary connection with the drive element. The second coupling partner is in a direct or indirect rotary connection with the driver.

Another embodiment of the tensioning device is characterized by means for adjusting the size of the pressure load between the coupling partners.

For a particularly simple design of the torque-dependent clutch, it is advantageous if the clutch partners are supported against one another in a pressure-loaded manner by at least one spring element. In this case, the spring element is preferably supported with its first end against a first spring seat and with its second end against a second spring seat. In this case, the distance between the spring seats can be adjustable in order to preselect the maximum transmissible torque from which the torque-dependent clutch interrupts the flow of force.

According to a further embodiment, friction surfaces supported flat against one another are formed on the coupling partners.

Another embodiment of the tensioning device provides a drive housing which encloses at least parts of the gear arrangement. The drive housing is fastened on the outside on a peripheral area of the support tube, on which the support tube is provided with an opening. A gear element of the gear assembly extends into the opening. This gear element is preferably in engagement with the driver.

According to a variant, the drive element and the torque-dependent clutch are arranged in the drive housing.

In an alternative variant, the drive element and the torque-dependent clutch are components of a clutch module that is detachably attached to the drive housing.

In this alternative variant, part of the clutch module is also a form-fit element which is in releasable engagement with a gear element mounted in the drive housing, the torque-dependent clutch being arranged between the drive element and the form-fit element.

Finally, it is proposed that the driver be a rotating sleeve which is arranged rotatably in the support tube and which is provided on its inside with positive-locking structures for connection to the threaded nut.

• 1 eine Schraubverbindung bestehend aus einem Gewindebolzen und einer Gewindemutter;
• 2 in einem Längsschnitt den prinzipiellen Aufbau des Spannzylinders der Spannvorrichtung;
• 3 in perspektivischer Ansicht die Spannvorrichtung, aufgesetzt auf die Schraubverbindung, sowie ein an die Vorrichtung angesetztes Handwerkzeug zum Nachziehen bzw. Beidrehen der Gewindemutter der Schraubverbindung;
• 4 einen Schnitt durch ein Antriebsgehäuse gemäß der Schnittebene IV - IV in 3;
• 5 das Antriebsgehäuse in perspektivischer Darstellung;
• 6 in perspektivischer Ansicht eine andere Variante der Spannvorrichtung, aufgesetzt auf die Schraubverbindung, sowie ein an die Vorrichtung angesetztes Handwerkzeug zum Nachziehen bzw. Beidrehen der Gewindemutter der Schraubverbindung;
• 7 einen Schnitt durch ein Kupplungsmodul gemäß der Schnittebene VII - VII in 6.

Embodiments of the invention shown in the drawings are explained in more detail below. Show it:

• 1 a screw connection consisting of a threaded bolt and a threaded nut;
• 2 in a longitudinal section the basic structure of the clamping cylinder of the clamping device;
• 3 a perspective view of the clamping device, placed on the screw connection, and a hand tool attached to the device for tightening or turning the threaded nut of the screw connection;
• 4th a section through a drive housing according to the section plane IV - IV in 3 ;
• 5 the drive housing in a perspective view;
• 6th a perspective view of another variant of the tensioning device, placed on the screw connection, as well as a hand tool attached to the device for tightening or turning the threaded nut of the screw connection;
• 7th a section through a coupling module according to the section plane VII-VII in 6th .

The screw connection after 1 includes a threaded bolt 2 who z. B. composed of an enlarged bolt head and a shank and a threaded portion, and one on the threaded portion of the threaded bolt 2 screwed on threaded nut 3 . The screw connection braces two machine parts here 5 , 6th against each other, which are for example two flanges.

Next to the threaded bolt 2 and the threaded nut screwed on it 3 Further elements can be part of the screw connection, for example another nut on the threaded nut 3 facing away from the machine parts to be clamped 5 , 6th . Additional washers can also be part of the screw connection.

By means of a clamping device 11 In the hydraulic clamping cylinder design, the screw connection is stretched lengthways by applying an exclusively axial tensile force. This is done by pulling axially on the threaded nut 3 protruding thread end section 2A of the threaded bolt 2 the threaded bolt 2 longitudinally stretched, the stretching mainly on the shaft and the threaded section of the threaded bolt 2 he follows. The tightening force and / or the tightening pressure applied by means of the hydraulics can be automatically stored in a documentation module using an evaluation unit, and is thus available for testing purposes.

While activating the clamping cylinder for a certain time, a predetermined preload force is applied to the threaded bolt 2 is exercised, the threaded nut 3 tightened or retightened. This so-called turning of the nut is done by hand using a hand tool 10 , e.g. B. a polygon wrench with or without an integrated ratchet mechanism. Also for turning the mother over 3 actually used tightening torque can be automatically saved in the documentation module.

One in the center of a cylinder housing 7th the clamping device arranged to be longitudinally movable 12th is internally threaded at one end 13 Mistake. With the internal thread 13 becomes the interchangeable socket 12th before the tensioning process on the over the nut 3 protruding thread end section 2A unscrewed. This screwing is also done with the hand tool 10 , including the interchangeable socket 12th a polygon drive at the other end 14th has to which the hand tool 10 lets start.

During the tensioning process, the is on the threaded bolt 2 screwed-on interchangeable socket 12th set under axial tension by hydraulic pressure, which causes the threaded bolt 2 stretches in its longitudinal direction. As a result, the bottom of the mother comes 3 from the pad 5A free. In this state, the mother can 3 Turn with relatively little resistance and until it rests on the surface again without any gaps 5A turn. The turning is done using the hand tool 10 . Its rotary or swivel movement is via an interposed gear arrangement 15th into a rotary movement of the threaded nut 3 is transmitted.

The immediate turning of the nut 3 takes place through one in a support tube 8th mounted driver 16 . The driver 16 is the mother in the embodiment described here 3 surrounding rotary sleeve, which is provided on its inside with form-locking structures and in particular with a hexagon, which is the one on the nut 3 Form-fitting hexagon grips around. The driver or the rotating sleeve is driven 16 by a gear element designed as a pinion 17th the gear arrangement 15th . The gear arrangement 15th is mostly located in a drive housing 18th , which is attached as a module on the outside of the clamping cylinder of the clamping device.

The hydraulic clamping mechanism is enclosed by the pressure-resistant cylinder housing 7th . Its rigid continuation downward forms the threaded nut 3 surrounding support tube 8th . The support tube 8th can be integral with the cylinder housing 7th be, or one opposite the cylinder housing 7th separate, e.g. B. an attached component. The support tube 8th is open on its underside and is supported with this underside on that solid base 5A on which the mother is also 3 supported with their underside.

On the cylinder housing 7th there is a hydraulic connection 20th over which a hydraulic work area 21st is valve-controlled with an external hydraulic supply, for example a hydraulic pump.

In the cylinder housing 7th is, sealed to the cylinder inner wall, a piston 25th Arranged movable in the longitudinal direction. By feeding hydraulic pressure into the hydraulic working space 21st of the clamping cylinder, the piston lifts 25th at. This can, for example, counter to the force of the piston 25th take place from above acting spring, which serves as a piston return spring and strives to the piston 25th to hold in its basic position, in which the hydraulic working space 21st has its minimum.

The piston 25th surrounds the interchangeable socket in a ring 12th . It is on its inner edge with a paragraph or a step 27 provided, the, the document 5A facing away, forms a driver surface on which the interchangeable socket 12th supports. The hydraulic pump feeds pressure fluid into the working space 21st so the piston rises 25th and takes the interchangeable socket 12th axially with. It comes to the longitudinal stretching of the threaded bolt 2 .

The interchangeable socket 12th is at its bolt-side end with the internal thread 13 for screwing onto the threaded bolt 2 Mistake. At the other end is the interchangeable socket 12th with the drive polygon 14th provided to which the hand tools 10 can be used to prepare the clamping process with the hand tool 10 the interchangeable socket 12th to turn and on the threaded bolt 2 unscrew.

For turning the rotating sleeve 16 has the support tube 8th on the circumferential area on which the drive housing is located 18th with the gear arrangement 15th is located, an opening 28 on. Through the opening 28 through it is therefore the rotating sleeve 16 driven. The gear arrangement 15th therefore forms together with the rotary sleeve 16 a device for turning the nut 3 . The mother 3 can of course only be turned in sensibly as long as the piston 25th is under hydraulic pressure.

The force required for turning is, for. B. by moving the hand tool designed as a ratchet wrench back and forth 10 , applied until a torque limit rules out any further increase. This is part of the gear assembly 15th a torque-dependent clutch 30th in the form of an overload clutch.

Based on 3 , 4th and 5 are details of the gear arrangement 15th described in a first embodiment.

In the drive housing 18th , which is on the outside of the support tube 8th is attached, the gear element are on two mutually parallel axes of rotation 17th and another gear element 37 stored. The gear elements 17th , 37 are intermeshing pinions. The gear element 17th also meshes with a toothing, which is on the outside of the rotating sleeve 16 is trained. For this purpose, the gear element protrudes 17th into the opening 28 ( 2 ) with which the support tube 8th is provided on this circumferential position.

The gear element 37 is designed in several parts and has, among other things, a tool surface 38 on to which the hand tools are attached 10 can start with its appropriately shaped tool surface.

The drive path within the gear assembly 15th is such that by means of the tool surface 38 applied hand tools 10 the gear element 37 is set in rotation, and this movement via the intermediate gear element 17th on the one in the support tube 8th mounted rotary sleeve16 is transmitted. Through the gear element 17th as an intermediate pinion it is ensured that the direction of rotation on the tool surface 38 is in the same direction as the direction of rotation of the threaded nut 3 when turning.

In the embodiment according to 3 , 4th and 5 is the torque-dependent clutch 30th into the gear element 37 integrated, which is in several parts for this purpose. Components of the multi-part transmission element 37 are a first disk provided with a toothing on its circumference 31 , one with the first disc 31 non-rotatably coupled second disc 32 and one between the discs 31 , 32 arranged, third disc 33 .

The three discs 31 , 32 , 33 with their friction surfaces lying flat against each other, they are the coupling partners of the overload clutch. The middle disc 33 forms the first coupling partner with its two friction surfaces. Furthermore, the one against the middle disk 33 adjacent flat side of the disc 31 a friction surface, and so is the one against the central disc 33 adjacent flat side of the disc 32 a friction surface. Therefore, the mutually rotatable disks form 31 , 32 jointly the second coupling partner, who via the intermediate gear element 17th in an indirect rotary connection with the rotary sleeve 16 stands.

According to 4th is the disc 31 not only the second coupling partner, but with its toothing it is also the pinion, which via the interposed gear element 17th the rotary connection to the rotary sleeve 16 manufactures.

The middle disc 33 the clutch is an integral part of one in the drive housing 18th rotatably mounted drive element 35 . On the drive element 35 is, here outside the drive housing 18th , that tool area 38 trained to use the hand tool 10 lets start.

Screws 36 with the screw axis parallel to the coupling rotation axis connect the outer disks 31 , 32 with each other without the middle disc 33 to touch. By tightening the screws 36 become the discs 31 , 32 pulled closer together, thereby increasing their pressure on the middle disc 33 elevated. This pressure and thus the friction between the discs 31 , 32 , 33 determines this from the torque-dependent clutch 30th maximum torque that can be transmitted until it slips.

In practice there is a change in pressure and thus in friction between the coupling partners 31 , 32 , 33 the overload clutch is rarely required or even undesirable. Hence the screws 36 for changing the clutch force only accessible if a cover is initially installed 39 is removed, which part of the drive housing 18th is. The lid 39 his part is by screws 40 secured.

Based on 6th and 7th is a second embodiment of the gear assembly 15th described.

In this embodiment, those are with the tool surface 38 for attaching the hand tool 10 provided drive element 35 and the torque-dependent clutch 30th Components of a coupling module 41 . The clutch module 41 is detachable from the drive housing 18th scheduled. The individual parts of the gear assembly 15th are partially located in the on the support tube 8th attached drive housing 18th , and partly in the separate coupling module 41 .

Part of the coupling module 41 is a one-part or multi-part housing 45 . The case 45 is, the drive element rotatable therein 35 turned away, with a rigid to the housing 45 trained form-fit element 42 is provided, e.g. a square. Is according to 6th the clutch module 41 to the drive housing 18th attached, the form-fit element engages 42 into a corresponding counter structure on the gear element designed as a pinion 37 ( 4th ).

The torque-dependent clutch 30th works in the second embodiment with two conical friction surfaces. The one with the tool surface 38 provided drive element 35 has a first cone. This forms the first coupling partner 43 the overload clutch. A corresponding cone on the one-part or multi-part housing 45 forms the second coupling partner 44 , which via the intermediate gear elements 37 , 17th in an indirect rotary connection with the rotary sleeve 16 stands.

The transmittable torque is adjustable, including a spring element 48 with its first end against the drive element 35 , and with its second end against a spring seat on the housing 45 supports. About twisting of the spring element 48 to avoid, the spring element is supported 48 on the housing side not directly against the housing 45 but against a thrust bearing 49 , which in turn is in the housing 45 is supported.

The distance between the spring seats and thus the length of the spring element 48 is adjustable. For this purpose is the case 45 divided into two parts and is made up of each other via a thread 47 screwed housing parts 45A , 45B together.

In both of the described embodiments, a transmission element of the transmission arrangement 15th be provided with a rotation angle sensor. This records an angle of rotation that occurs in the course of tightening the nut 3 is covered in total until the maximum torque value is reached. The detected angle of rotation can either be the angle of rotation of the rotating sleeve 16 and with it the mother 3 be itself, or an angle of rotation that one of the rotating gear elements of the gear arrangement 15th executes. The angle value recorded in this way can also be stored in the documentation module.

List of reference symbols

2

Threaded bolt

2A

Threaded end section

3

Nut, threaded nut

5

Machine part

5A

document

6th

Machine part

7th

Cylinder housing

8th

Support tube

10

Hand tools

11

Jig

12

Interchangeable socket

13

inner thread

14th

Multi-edge drive

15th

Gear arrangement

16

Driver, rotating sleeve

17th

Gear element

18th

Drive housing

20th

Hydraulic connection

21st

working space

25th

piston

27

step

28

opening

30th

Torque-dependent clutch

31

Disc, second coupling partner

32

Disc, second coupling partner

33

Disc, first coupling partner

35

Drive element

36

screw

37

Gear element

38

Tool area

39

cover

40

screw

41

Coupling module

42

Form-fit element

43

Konus, first coupling partner

44

Cone, second coupling partner

45

casing

45A

Housing part

45B

Housing part

47

thread

48

Spring element

49

Thrust bearings

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102004043145 B3 [0002]
• WO 2008/092768 A2 [0002]
• WO 2010/054959 A1 [0003]
• US 5452629 [0004]

Claims (13)

Clamping device for a screw connection consisting of a threaded bolt and a threaded nut, with a support tube (8) surrounding the threaded nut, a cylinder housing (7) as an extension of the support tube (8), a piston (25) movable in the cylinder housing (7) by means of hydraulic pressure, an interchangeable bushing (12) which can be axially carried along by the piston (25) and is provided with an internal thread (13) for screwing the interchangeable bushing (12) to the threaded bolt; connectable driver (16), and a gear arrangement (15) between a drive element (35) rotatably mounted outside the support tube (8), which is provided with a tool surface (38) for attaching a hand tool (10), and the driver (16), characterized in that part of the gear arrangement (15) is a torque-dependent clutch (30). Clamping device according to Claim 1 , characterized in that the torque-dependent clutch (30) is an overload clutch, preferably a slip clutch. Clamping device according to Claim 1 or 2 , characterized in that components of the torque-dependent clutch (30) are pressure-loaded coupling partners supported against each other, a first coupling partner (33, 43) in a direct or indirect rotary connection with the drive element (35), and a second coupling partner (31, 32 , 44) rotates in an indirect or direct rotary connection with the driver (16). Clamping device according to Claim 3 , characterized by means (36, 48) for adjusting the size of the pressure load between the coupling partners (33, 43, 31, 32, 44). Clamping device according to Claim 3 or 4th , characterized in that the coupling partners (43, 44) are supported against one another in a pressure-loaded manner by at least one spring element (48). Clamping device according to Claim 5 , characterized in that the spring element (48) is supported with its first end against a first spring seat and with its second end against a second spring seat, and that the distance between the spring seats is adjustable. Clamping device according to one of the Claims 3 - 6th , characterized in that friction surfaces supported flat against one another are formed on the coupling partners. Clamping device according to one of the preceding claims, characterized by a drive housing (18) which encloses at least parts of the gear arrangement (15) and which is fastened outside on a peripheral region of the support tube (8), on which the support tube (8) is provided with an opening (28) is, wherein a gear element (17) of the gear arrangement (15) extends into the opening (28). Clamping device according to Claim 8 , characterized in that the gear element (17) is in engagement with the driver (16). Clamping device according to Claim 8 or 9 , characterized in that the drive element (35) and the torque-dependent clutch (30) are arranged in the drive housing (18). Clamping device according to Claim 8 or 9 , characterized in that the drive element (35) and the torque-dependent clutch (30) are components of a clutch module (41) detachably attached to the drive housing (18). Clamping device according to Claim 11 , characterized in that part of the clutch module (41) is also a form-locking element (42) which is in releasable engagement with a gear element (37) mounted in the drive housing (18), the torque-dependent clutch (30) between the drive element ( 35) and the form-fitting element (42) is arranged. Clamping device according to one of the preceding claims, characterized in that the driver (16) is a rotating sleeve which is rotatably arranged in the support tube (8) and is provided on its inside with positive-locking structures for connection to the threaded nut.

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